The long-term goal of this study is the development of preventive or therapeutic measures for benign prostatic hyperplasia (BPH). The principal specific aim is estimation of the effect of cigarette smoking on the rate of surgery for BPH. A case-control study is proposed to achieve this aim. Men under age 80 years who have had their initial operation for BPH in a 21-month period will be identified on a state-wide basis in Rhode Island, and controls will be selected at random from lists of male residents of the state, with frequency matching by age. Cases (1000) and controls (2000) will be interviewed by telephone regarding their cigarette-smoking histories and other selected environmental exposures. Relative and attributable risks of surgically-confirmed BPH will be estimated in current smokers and ex-smokers, compared to nonsmokers, and risks will be evaluated according to amount smoked and to time since stopping. Slides of the prostatic tissue removed will be reviewed according to a standard protocol in order to assess the features of the hyperplastic component, especially the epithelium, and other benign changes. The effect of cigarette smoking will be evaluated for sub-types of BPH with different histologic features. Based on information obtained from the controls, cigarette smoking also will be related to the development of symptoms of BPH not treated surgically. Finally, associations of BPH with coffee-drinking, alcohol consumption and occupation will be explored.